The assembly of foil-like turbine blades into torque converter turbine drums for use in automobile transmissions and similar applications has long presented difficult assembly problems to torque converter manufacturers. Such torque converter assemblies generally include a dish-like turbine drum or housing that resembles the outer half portion of a shell of a toroid which has been split in half in a plane perpendicular to the central axis of the toroid. A ring of turbine blades, located inside the concave turbine drum, imparts or receives fluid pressure in response to movement of other parts of the torque converter. Such torque converter turbine blades are typically curved in three planes and secured within the dish-like turbine drum in non-radial positions.
Specially designed automatic assembly machines have been developed for assembly of torque converters due to the necessary precision and speed at which the turbine foils or blades are to be inserted into the dish-like turbine drum. However, it has been necessary to individually design an automatic assembly system for each blade and drum combination manufactured. Each automatic assembly machine is particularly adapted for the assembly of the unique combination of a certain size and type of turbine blade to be positioned and inserted into a particular size and type of turbine drum. Some examples of such assembly systems and methods are set forth in the following patents, all of which are assigned to the assignee of the present invention: U.S. Pat. Nos. 3,668,773--Achterberg; 3,691,618--Achterberg et al.; and 3,681,837--Franklin. These three patents are hereby incorporated by reference.
The Achterberg '773 patent discloses an assembly machine and method wherein a drum or housing is angularly indexed to successive positions as it is rotated about a fixed axis. A turbine blade is taken from a feeding magazine and is carried by a clamp attached to an offset load arm, which is mounted for oscillatory rotation about a load arm shaft. Rotation of the load arm shaft causes the offset load arm to present the blade in a rolling arcuate path to the drum, such that tabs provided on the blade may be inserted into slots in the drum.
The Achterberg et al. '618 patent discloses an automatic assembly machine and method in which the turbine blades are deformed and held by a linear transfer device prior to inserting a first blade ear into a drum, thereby locating the blade in a preliminary position prior to hammering the blade into its finally assembled position in the drum. After the blade has been placed in its preliminary position in the drum, the blade is permitted to spring toward its final position, and is then driven by a mechanical blow provided by a hammer-like operating member of the assembly machine.
Finally, the Franklin '837 patent discloses a similar automatic assembly system, wherein a first hammer mechanism is used to cam and hammer a first blade ear into a preliminary position in a drum. The blade is then urged into its finally assembled position in the drum by the camming and hammering motion of a second hammer.
In the automatic assembly machines set forth in the three above-mentioned patents, the torque converter drum is supported for rotation about a fixed axis, whereby it may be incrementally rotated to present a slot therein for receipt of a tab on the foil-like blades which are inserted by a transfer device having a linear motion. Due to the inherent limitations of the linear-action machines in attempting to perform the complex insertion motions required to insert curved blades into a curved drum, the design of such assembly systems has been quite difficult. Moreover, due to the complex part geometries and the part tolerance interrelationships, it is often necessary that the curved turbine blades be assembled into curved turbine drums by hand or, alternatively, that they be assembled with the assistance of relatively elementary equipment which cannot be operated automatically.
While prior blade-insertion systems have been designed as described in the above-mentioned patents to accomplish the desired task, the precision necessary in the presentation of the blade to the drum has required that a separate assembly machine be designed for each specific combination of turbine blade and drum. Furthermore, the tolerances are often so precise that if the blades (which are intended to be identical) are made on stamping presses with different dies, the slight variations in the blades made with the different dies frequently necessitates that an assembly machine be re-adjusted or re-calibrated for the insertion of blades made from the different stamping die.
Thus, it would be most desirable to provide an automatic assembly machine, particularly one for use in assembling foil-like blade inserts into a torque converter turbine drum, which could be readily adapted for use in assembling a variety of turbine blades with a variety of turbine drums. It would also be desirable to provide such an assembly machine having the necessary precision for insertion of the blades with respect to the drum, without the need for precise construction of the components of the assembly machine, or the even more precise readjustment of the components of the assembly machine during the manufacturing process.